View full sizeAn Australian A330 MRTT simultaneously refuels two F/A-18 fighters via its all-digital hose-and-drogue refueling pods under each wing. EADS North America says the same system will be used on the KC-45. (AP Photo/file)

The European Aeronautic Defence and Space Co. will win the U.S. Air Force tanker contract over rival Boeing Co., according to a leading defense analyst.

Loren Thompson of the Lexington Institute in Arlington, Va., said EADS has emerged as the clear favorite for the coveted deal, based on the Air Force's internal analysis of the two competing bids.

"Boeing has lost this competition," Thompson said, citing conversations with Boeing executives. "The only question now is whether they choose to protest the award, and I'm not sure they will."

Neither Boeing nor EADS would comment Sunday.

The Air Force said it expects to announce a winner for the potential $40 billion contract as early as next month. Chicago-based Boeing and EADS, the parent company of Airbus, are vying for the lucrative work to build 179 jet tankers for the Air Force.

It's the second round of competition between the American and European defense giants in a contest marked by fierce political fighting and prodigious marketing campaigns.

The battle has big stakes in Mobile. EADS has said that, if successful, it plans to assemble its KC-30 tankers at a $600 million, 1,500-worker factory to be constructed at Brookley Field.

Boeing has proposed to assemble its KC-767 tankers on its existing commercial assembly lines in Everett, Wash., and modify them for the military in Wichita, Kan.

EADS, then part of a team led by Northrop Grumman Corp., won the tanker contract in 2008. But the deal unraveled after federal auditors, acting on a protest filed by Boeing, found problems with the way the Air Force conducted its review.

That led to a new competition beginning in July, when Boeing and EADS submitted new bids on the contract.

Thompson said Boeing executives concluded last week - after getting a look at the Air Force's technical analysis of the two competing planes - that they were beaten.

The Air Force sent the confidential analysis, known as an Integrated Fleet Aerial Refueling Assessment, to each of the companies in mid-November. But it mistakenly included a disk containing the Boeing analysis in the package shipped to EADS, and vice versa.

Both companies acknowledged that they received the errant disks and said they notified the Air Force as soon as they became aware of the mistake.

The Air Force called the mix-up a "clerical error" and said it took steps to ensure that neither side was put at a disadvantage. One of those steps, according to the Air Force, was to release the Boeing analysis to EADS and the EADS analysis to Boeing.

"We gave both competitors equal access to the information," Air Force spokesman Col. Les Kodlick said. "We view that as leveling the playing field."

Thompson, who has advocated for Boeing in the tanker contest, said Friday that he spoke to Boeing officials close to the competition. He said that, after reviewing the data, they concluded that EADS held a substantial edge in the Air Force's assessment.

"Basically they saw how they stacked up in the warfighting effectiveness analysis, and they did not stack up well," Thompson said. "The Air Force continues to favor the larger plane" offered by EADS.

The IFARA analysis is based on a complex computer modeling program that measures the effectiveness of each plane in a series of battlefield scenarios. The score could weigh heavily in a tight competition between two aircraft that offer different features.

Boeing has promoted its smaller KC-767 as "optimum sized" for the Air Force's needs, able to land on more runways and bring fuel closer to the front lines of combat.

EADS has touted the greater capability of its KC-30, a bigger plane that can carry larger amounts of cargo and passengers in addition to fuel.

Thompson said Boeing had some objections to the way the Air Force structured the analysis, but that the company's greater concern was a "pattern of bias" that appeared to skew the competition in favor of EADS.

A chief complaint, he said, was the Air Force's decision to exclude as a factor in the competition a recent ruling by the World Trade Organization that Airbus received illegal subsidies from European governments.

But Thompson said Boeing may have a difficult time proving - for a second time - that the tanker competition was flawed.

"In the first round, the errors were so fundamental and obvious," he said. "The pattern is much more subtle this time."

The Air Force dismissed Thompson's accusation of bias.

"We are continuing to work hard to ensure a fair and open competition for the tanker contract, and absolutely take issue with any suggestion to the contrary," Kodlick said.